Generally, in electronic or electrical apparatuses or devices, when a board is mounted on a chassis or when another board is further mounted on the board, rigid posts with screws have been used for holding the board spaced apart from the chassis or for spacing and holding the boards. Thus, there is a problem that attachment of boards is troublesome.
Prior art structures have been provided to solve the above-mentioned problem. For example, a board fastener 1 shown in FIGS. 10 and 11 has been proposed (G.B. Pat. No. 1 541 448). FIG. 10 is a side view of the board fastener, and FIG. 11 is a sectional view thereof, taken on line XI--XI of FIG. 10. In the drawings, a first board securing member 5 (a pair of diverging wings) for securing a first circuit board 4 is provided on the lower surface 3 of a base 2. A rigid upstanding post 8 for spacing the first circuit board 4 and a second circuit board 7 is formed on the upper surface 6 of the base 2. An elongated shaft 9 is formed above the post 8. A resilient arm 10 extends upwardly from a post rib 8a projecting from the upper surface 6 of the base 2. A resilient locking tooth 11 for locking the second circuit board 7 is integrally formed on the arm 10. The arm 10 and the locking tooth 11 are made of synthetic resin.
In securing the second circuit board 7, as shown in FIG. 10, the elongated shaft 9 enters an aperture 12 in the second circuit board 7 while the second circuit board 7 is pressed downwardly. The resilient arm 10 is pushed open by an edge 13 of the second circuit board 7, and a reverse detention member 11a that is part of the locking tooth 11 then engages the edge 13 of the second circuit board 7. Thus, the second circuit board 7 is easily secured by co-operation of the locking tooth 11 and the post 8.
The board fastener 1 described above, however, has a problem that removal of the second circuit board 7 from the board fastener is troublesome, although mounting thereof is easily accomplished. To remove the second circuit board 7, the second circuit board 7 must be pulled up while the edge 13 of the second circuit board 7 is drawn apart from the reverse detention member 11a by force applied on a barb 11b of the locking tooth 11.